Can computer models predict the past?

New study increases concerns about climate model reliability

ROCHESTER, NY (Dec. 11, 2007) A new study comparing the composite output of 22 leading global climate models with actual climate data finds that the models do an unsatisfactory job of mimicking climate change in key portions of the atmosphere.

This research, published on-line Wednesday in the Royal Meteorological Society's International Journal of Climatology*, raises new concerns about the reliability of models used to forecast global warming.

The usual discussion is whether the climate model forecasts of Earth's climate 100 years or so into the future are realistic, said the lead author, Dr. David H. Douglass from the University of Rochester. Here we have something more fundamental: Can the models accurately explain the climate from the recent past? It seems that the answer is no.

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The 22 climate models used in this study are the same models used by the UN Intergovernmental Panel of Climate Change (IPCC), which recently shared a Nobel Peace Prize with former Vice President Al Gore.